Man has long desired to possess a simply structured watercraft which would allow him to use his weight and leg strength, as by a pedalling operation, to power the craft. Various devices, sometimes referred to as pedalogs, have been proposed, but these have various inadequacies. Some turn a screw propellor which usually provides little water-moving surface, and this is inefficient using the limited power available to a single person. Some rotate a large wheel, but these are bulky. It has not heretofore been possible to provide a simple and easily transportable structure which would allow limited foot movement to provide an extended powered path through the water.